purple-brown vs purplish-brown

purple-brown and purplish-brown both are adjectives.

Word	Noun	Adjective	Verb	Adverb
purple-brown	No	Yes	No	No
purplish-brown	No	Yes	No	No

As adjectives, purple-brown and purplish-brown are synonyms defined as:

purple-brown (adjective)	purplish-brown (adjective)
of brown tinged with purple	of brown tinged with purple